Natural gas as an alternative fuel and gearboxes for electric motors were two
of the issues addressed at this year's Cenex low-carbon-vehicle event.

The heat has gone out of the business of saving-the-planet these days as car makers batten austerity hatches. As a result, the recent annual Cenex low-carbon vehicle conference and exhibition was commensurately low-key.

Missing in action were Honda with its excellent FCX Clarity, or Hyundai with its ix35 fuel-cell car. Even Daimler, with its near-production-ready fuel-cell B-class, was a late entry. Robert Evans, the Cenex CEO, admits that the alternative fuel world is a little quieter these days, but there’s no shortage of research and development going on.

“We’ve still got to have the right product in five or six years, so we need that R&D,” says Evans. “There’s everything to fight for and I don’t see companies saying 'don’t offer us any more money because we can’t match the funding’. It’s closer to market where the economic problems are raising their heads. There’s not a huge pent-up demand for alternative fuel vehicles as the conventional car already fills the demand for mobility. And yes, the sector would be a lot stronger if the economy was stronger.”

We went to the event with a couple of questions in mind, however. First, what happened to good old natural gas? Despite its strength as a transport fuel in Asia, South America and, weirdly, Italy, the fuel has never really caught on in the UK, although 25 years ago what was then British Gas gave it a good punt.

Natural gas, or methane, has a lot going for it as a transport fuel. It burns cleaner than petrol or diesel, it’s in ready supply (especially through the controversial new technique of shale-gas extraction by hydraulic fracturing of rock or “fracking”), engines specifically designed for the fuel can be as powerful as a conventional units and it saves (some) carbon dioxide. So why aren’t we all using it?

We asked Norman Leece, the managing director of Gasfill in Warwickshire, which markets small- and medium-sized gas compressor/refuellers for domestic and industrial use. “When British Gas first tried to promote the fuel it was a monopoly,” he says, “which meant it had lots of money and was looking to promote North Sea gas. Then the monopoly was broken up, lots of businesses lost interest and, yes, there were some technical horror stories with refuelling back then.”

Leece claims that with a worldwide population of about 15 million gas-powered vehicles and annual growth figures near 20 per cent, there’s a lot of interest in the fuel. “There are about 45 production compressed natural gas (CNG) vehicles on sale in Europe, but the UK has issues with right-hand drive and the infrastructure,” he says.

Evans agrees with Leece’s optimism and believes there is “huge potential” for gas in the haulage sector, but that this time it will be different from the failed attempts to attract fleet managers in the past. “Installed in high-throughput 'corridors’, this could be a highly profitable area for the oil companies and haulage firms,” he says. “The US achieved a natural-gas breakthrough with just such dedicated corridors backed by the Obama administration.”

But where does this leave us ordinary motorists? Sitting pretty if you can access the fuel – and most people have a domestic supply, which (and whisper this) is exempt from road-fuel duty.

“We reckon natural gas is between 55 and 60 per cent of the cost of petrol,” says Leece. At present the Gasfill wall-mounted home compressor costs £5,000 plus VAT, but he wants to get that down to between £2,000 and £2,500. “But you can rent them, or share them,” he says. It takes 10 hours to fill a typical pressurised gas tank from a home unit, which will give a range of more than 200 miles. Shared between four people driving an average mileage, they would only need to fill up two to three times a week. “You could run four vehicles doing 12,000 miles a year with one of these units,” he says, “and the payback would be in months.”

Our other question concerned gearboxes, or more exactly two-speed transmissions for electric vehicles. It’s not well known, but at high revolutions electric motor efficiency falls off a cliff, which is partly why they are limited in top speed and have such lacklustre performance above 50mph. Up to now we had understood that the lack of any production multi-speed transmissions was because electric motors produce so much gear-stripping torque. Not so, according to the hugely experienced Clive Woolmer, general manager of British transmission specialist Xtrac.

Xtrac produced the neat single-speed transmission package for Infiniti’s Emerg-e which we drove before the Goodwood Festival of Speed. Woolmer admits that a two-speed unit would be about half as big again, but given the compact size of the existing unit, that wouldn’t be a problem. What would be an issue, however, is the inertia of the motor. “It’s the torque reversal,” says Woolmer. “You’ve got a motor spinning at up to 14,000rpm, which you have to stop and speed up again in milliseconds. That’s a massive energy dump, which the power electronics have to handle, and it means you completely lose the seamless quality of the electric drive.”

Woolmer says that the problem is being worked on, but the solution is not clear cut. “Some companies are working on clutches in the transmission, but we don’t agree. There are some racing solutions we are looking at where the target is a seamless and silent change quality.” Needless to say, he wouldn’t elaborate any more, but at least we now know why EVs don’t have gearboxes for the moment.